LaTeX resources:
Mac OSX: Get MacTeX here. Scroll down to "Trying out
Tex" for demos.
Windows: You'll need two files: The MiKTeX program, and some
editor.
Download sites with full instructions and lots of examples can be found
here.
Or, to obtain the files directly, get
1. MiKTeX and
2. some editor, such as: WinEdtor TeXnicCenter.